Signs of Hearing Loss
The signs of hearing loss may be categorized as either conductive or sensorineural. Conductive hearing loss is any kind of pathology affecting the sound conduction mechanism located between the outer ear and cochlea, including the middle ear. Sensorineural hearing loss is any kind of pathology affecting the inner ear nerve pathways to the brain, including the cochlea.
In addition, there are different types of hearing loss based on severity and frequency range:
1) MILD – 16 to 25 dB HL
2) MODERATE – 26 to 40 dB HL
3) SEVERE – 41+dB HL.
Mild hearing loss can be very difficult to detect in someone with good speech discrimination skills. This is because mild loss generally does not affect the ability of technicians conducting audiometric evaluations to understand what a person says, especially when they are facing them and speaking slowly.
Moderate hearing loss can result in reduced ability to understand conversation by telephone or in noisy environments; however, unless a person must communicate by telephone on a regular basis, these communication issues usually go unnoticed. Detecting moderate hearing loss can be difficult even for audiologists and patients with this type of loss.
Severe or profound hearing loss (hearing that is worse than 90 dB HL) may result in the inability to understand speech even when it is loud enough to hear. In addition, a person can suffer from hyperacusis (increased sensitivity to loud sounds) and phonophobia (fear of noise).
1) Conductive hearing loss – any impairment in the conduction mechanism between the outer ear and cochlea.
2) Sensorineural hearing loss – any impairment of the nerve pathways from the inner ear to the brain.
3) Mixed hearing loss – coexisting conductive and sensorineural hearing losses.
4) Central hearing loss – associated with injury or damage to central parts of the auditory system, including the brainstem.
An audiogram is a graph of air conduction thresholds of an individual over a specified frequency range. Air conduction thresholds are measured in decibels (dB) and hearing loss is usually presented as the number of decibels at which the threshold occurs compared to a standard value.
The causes of conductive hearing loss are ear infections, wax impaction, damage to the tympanic membrane, otosclerosis, and perforated eardrums. Sensorineural Hearing Loss can be caused by Meniere’s disease, noise exposure, medications, aging changes, or autoimmune disorders. Mixed hearing loss can be caused by a combination of the conductive and sensorineural types of hearing loss.
Central Hearing Loss can be caused by head trauma, stroke, brain tumors. It is also associated with autoimmune disorders such as the Ramsay Hunt Syndrome which causes facial paralysis on one side of the face.
Even though there are different types of hearing loss, some tests are used to determine whether someone has hearing loss. Because hearing impairment can be either sensorineural or conductive, testing may involve either air conduction threshold testing or bone conduction threshold testing.
The Rinne test, also known as the Stenger test, tests for the sensory type of hearing loss with both air and bone-conducted tones.
The Weber test, also known as the Rinne-Weber test, tests for the conductive types of hearing loss with both air and bone-conducted tones.
For audiometric evaluations in children younger than three years old, immittance testing is used because it assesses the ability to transmit sound through the ear canal, middle ear, and tympanic membrane and is less likely to be influenced by a child’s behavior or movement.
Mild Hearing Loss – 16-25dB HL
May be able to detect high-frequency sounds but not low frequencies.
May have trouble with conversations, especially if there is background noise.
May need to turn the volume up on the TV or radio.
May not be able to hear whispered speech, but may be able to understand someone speaking with lips touching their ear.
Moderate Hearing Loss – 26-40dB HL
Perceives high frequencies better than low ones.
Mild trouble understanding conversations in even quiet rooms, especially on the phone or if someone has an accent.
May need to turn the volume up on the TV or radio.
May not be able to hear whispered speech, but may be able to understand someone speaking with lips touching their ear.
Severe Hearing Loss – 41-70dB HL
Can hear loud sounds, but most softer sounds are difficult or impossible to hear.
May not be able to hear the voices of women and children.
May require hearing aids or other amplification devices to communicate fully in a quiet room, and may still need these devices even in a moderately noisy room.
Can understand speech with their back turned to the speaker if they can read lips and facial expressions.
Profound Hearing Loss – 71-90dB HL
Can hear faint sounds, but most softer sounds are difficult or impossible to hear.
May not be able to hear sound at all if someone’s lips do not touch their ear when speaking.
May need hearing aids or other amplification devices to communicate fully in a quiet room. May still need these devices even in a moderately noisy room.
May not be able to hear whispered speech, but may be able to understand someone speaking with lips touching their ear.
Very Profound Hearing Loss – 91-110dB HL
Can only hear extremely loud sounds such as alarms and sirens.
Types of Hearing Problems:
1. Sensitivity to Loud Noises
2. Poor Speech Perception
3. Poor Sound Localization
4. Tinnitus (ringing in the ears)
5. Hyperacusis (oversensitivity to sounds)
6. Misophonia (a strong dislike of certain sounds)
Of all the types listed, hyperacusis has been seen in many cases to be the hardest type to deal with because it’s so widespread and changes how people live their lives by limiting everything from socializing to going out in public.
It is difficult for a person with hyperacusis to be in a bar, party, club, restaurant, or any other environment where they would have to deal with loud noises.
Tinnitus is the perception of sound when no actual external noise or sound is present. It is often referred to as “ringing in the ears.” Tinnitus can be caused by a variety of different factors.
One such factor is overexposure to loud noises, which can damage the microscopic endings of the hearing nerve in the inner ear and cause permanent hearing loss. If you think you have tinnitus, it’s important to figure out how severe it is and its exact cause so that you know your best course of action to take for treatment.
In most cases, tinnitus can be treated or improved upon with a combination of therapies and medications. For example, the most common treatment for tinnitus is a hearing aid, which can make low-level sounds louder and may improve your ability to hear and communicate with others.
Another way that tinnitus can be treated is through a therapy called tinnitus retraining therapy. Tinnitus retraining therapy involves using a combination of counseling and sound therapy to help your brain learn not to focus on the noises you’re hearing.
Hyperacusis is an intolerance of certain volume levels of everyday sounds that most people do not notice or find uncomfortable, such as chewing, crumpling paper, or rustling dresses.
These everyday noises become painful and sometimes even intolerable to the people suffering from this disorder, making them shy away from social situations, family gatherings, or public places. Those who suffer from hyperacusis may also be overly sensitive to loud noises, which can lead to further hearing problems.